The idea of a new hub airport should be dropped and three runways built immediately at airports in south-east England, according to the chief executive of Ryanair, Michael O'Leary.

O'Leary told MPs on the transport select committee that the argument for expanding only one central hub was driven by high-fare airlines and operators seeking to shunt passengers through Heathrow, and that new runways should be built at Stansted and Gatwick as well as Heathrow.

"London has the benefit of multiple airports, it has the infrastructure in place – get on and build three more runways," he said.

Asked what he thought of proposals for a new hub, which the mayor of London, Boris Johnson, has backed in the Thames estuary, O'Leary replied: "In parliamentary language it would be unprintable. Insane, stupid, harebrained." He said the need for new surrounding infrastructure alone made it all but unworkable.

Private investors would pay for new runways at existing airports "in a flash", he said, so long as they were free from the current regulatory regime.

The Ryanair boss said decades of mishandled policy meant the UK had lost out on much of the growth in the number of passengers using his airline, which had switched operations to other countries due to high airport charges and taxes.

He hit out at the Civil Aviation Authority (CAA), saying: "Shut it down tomorrow as far as economic regulation goes. It has been a disaster." He said its economists had "no grounding in reality and don't know much about air transport at all".

O'Leary said the Howard Davies commission, set up to consider the need for new airport capacity in the south-east, was "just another example of the UK government kicking the aviation strategy can further down the road" with "years of fudge and dither".

He reiterated his opposition to air passenger duty, which he claimed was counterproductive. "Instead of getting the visitors into the country and taxing them when they're here, you guys are standing by the runway like latter-day highway robbers."

Giving evidence alongside O'Leary, Dale Keller, chief executive of the Board of Airline Representatives, said he would support O'Leary's aspiration for runways at different airports. But he said most UK airports were functioning as efficiently as possible on limited capacity, and a bigger hub was crucial. "We need at least one airport with three or more runways," Keller said.